A conventional virtual-machine monitor (VMM) typically runs on a computer system and presents to other software the abstraction of one or more virtual systems or machines. Each virtual machine may function as a self-contained platform, running its own “guest operating system” (i.e., an operating system (OS) hosted by the VMM) and other software, collectively referred to as guest software. The guest software operates as if it were running on a dedicated computer system rather than a virtual machine. That is, the guest software expects to control various events and to be able to access various hardware resources